Straight line draw animation how doing it?
You can add a Bezier Curve and make it any shape you want to. SHFT +A > Curve > Bezier.



"Extrude" it to add some width.



Then Animate the start and/or end of the Bevel Factor. Hover your mouse over the Start or End input box of the Curve press I move the Playhead in the Timeline, change the value and hover your mouse over the Start or End input box press I again.